The present invention relates to the art of document security. It finds particular application in conjunction with the prevention and detection of counterfeiting and alteration of charge or credit cards. However, it is to be appreciated that the present invention has broader applications including identification cards, banking and money transfer cards, passports, key cards, and other documents and structures which are to be monitored and protected against alteration and forgery.
To enable credit card handling apparatus to be used with a plurality of different credit cards, substantially all commonly used credit cards have been standardized at 33 mils thickness. Although numerous antialteration and counterfeiting systems for credit cards have been suggested in the past, most of these systems would require the credit cards to exceed the 33 mil thickness standard. Because such thicker credit cards would be incompatible with equipment already in the field, such systems have been unacceptable.
The prior art credit cards commonly include a conventional ferrous oxide recording layer along an exterior surface. The cardholders name, account number, credit limit, and other such useful information are recorded on the recording layer. However, because ferrous oxide has a low magnetic coercivity and little magnetic memory, these recordings are readily erased and rerecorded. Thus, the ferrous oxide layer is itself subject to alteration and counterfeiting.
Another system for inhibiting fraud and counterfeiting includes the incorporation of a holographic image embedded in the card. However, holographic equipment is relatively expensive. Other cards have included magnetic or magnetizable materials embedded therein in a selected magnetic pattern. Still other cards have used mechanical counterfeit and alteration inhibiting means such as detailed engraving patterns, visible threads embedded in the plastic, and other mechanical structures which are readily destroyed or rearranged during alteration.
Although these prior art credit cards inhibit alteration and counterfeiting, they are still vulnerable to the dishonest merchant. They lack a suitable method for verifying that the merchant has checked the anti-tampering and anti-counterfeiting features of the credit card. Presently, merchants are required to compare credit card numbers with a book of bad numbers and/or confirm the credit card number with a central or regional authorization center. If the merchant complies with these requirements, he is reimbursed by the credit card company, even if the merchant chooses not to notice an obvious or third rate alteration of the credit card.
The present invention provides an improved credit card structure and verification system which overcomes the above-referenced problems and others. It provides for quick, effective verification that the card is authentic and that the embossed numbers are genuine and original.